JPS58112811A - Pneumatic tire - Google Patents

Abstract

PURPOSE:To prevent the separation of bead cores from carcass plies in a tire which includes the plural bead cores and receives prescribed bead core load and to promote the durability of the tire, by providing a flipper in a prescribed manner between the bead cores and the carcass ply cords. CONSTITUTION:In a pneumatic tire including a plurality of bead cores 4, each of which receives load of 6.0kg/cm<2> or more per unit length, a sheet of organic fiber flipper 2 woven like a rattan blind is embedded in rubber between the bead cores and carcass plies 5. The distance l between the bead core 4 at the butt of the bead and the ply cord 5 is set at 0.8-3mm.. At least one third of the total circumference of the bead cores 4 is surrounded by the flipper 2. According to this constitution, the force which acts between the bead cores 4 and the plies 5 is dispersed so that layer separation is prevented even if the load of 6.0kg/cm<2> or more acts. This results in enabling the decrease in the number of the bead cores and the promotion of the durability of the tire.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention has one or more pairs of bead cores in the bead portion, and a carcass ply cord connecting these pairs of left and right bead cores is made of organic fiber.

The load per unit length on one bead core is 4,
This relates to modification of pneumatic tires with a rating of Okg/as or more.

Conventionally, the carcass fly cord that connects the bead cores at the left and right bead portions is composed of organic fibers, and in pneumatic tires where the load applied to one bead exceeds 4,000 kg/egg, the cord and bead core are connected at the bead portions of the ply cord. This often results in interlayer separation between the beads, and eventually the plastic cord breaks around the bead core. Normally, measures have been proposed to reduce this load and prevent the ply cord from breaking.1 For example, increasing the tire rim diameter or increasing the number of bead cores has been proposed, but this will improve tire productivity. , undesirable from the point of view of resource conservation〇Also, some manufacturers have sold tires with a load on a pair of bead cores exceeding 4.0 kg/csg, but their durability after retreading is still insufficient. The purpose of the present invention is to disperse the force acting between the carcass ply and the bead core to prevent separation between the bead core and carcass ply even when the load is 6,01- or more, and thereby reduce the number of bead cores. The objective is to provide a bead structure that reduces the number of tires and improves durability, thereby improving tire productivity.

The 9-piece tire of the present invention that titrates this purpose has one or more pairs of bead cores in the bead portion, and the carcass ply cord that connects these pairs of left and right bead cores is made of organic fiber, and the single bead core In a pneumatic tire in which the load per unit length is 4.0 kg/cm or more, the minimum distance between the bead core's bead pace side portion and the ply cord is 0, I between the bead door of the bead portion and the ply cord. torn or higher and the maximum value is J
, Q'lllLm or less, one or more sudare weave or organic fiber layer (fritzber) is provided so as to surround three or more turns of the bead core. Various methods have been proposed to prevent destruction or interlayer separation.

For example, qI#bunshosan! Publication No. 1724' discloses a tire that prevents the carcass at the bead from separating from the surrounding rubber, but this tire has a 1IIK buffer layer on both sides of the carcass at the bead, Although it prevents the carcass from separating from the rubber material, it is difficult to leave a uniform gauge between the bead wire and the carcass ply cord, that is, to provide a uniform buffer layer, and the buffer layer is not inserted as a stiff fiber layer. In the Japanese Patent Application Publication No. 2003-1111, which is unfavorable from the viewpoint of tire productivity, such as reducing the rigidity of the bead and requiring a wire chafer, a limiter on the length of the flipper is set using a flipper. discloses that it reduces the separation of carcass ply cords, but there is no mention of flipper driving.
This is not entirely satisfactory as separation between the bead cores on the carcass plies can lead to failures in ply cutting.Also, it has been conventionally practiced to distribute electricity between the bead cores and the plies using a layer of sudare weave. Regardless of the load on the bead core, its purpose is, for example, JP-A-416-7.
As described in Publication No. 1404, it can be used as an independence improving member to integrate the bead core and epex, a reinforcing layer to prevent separation of the ply cord, or a reinforcing layer to reduce bead rim slippage. There was.

In the present invention, one or more woven organic fiber layers (
A frits bar) is embedded in a rubber material, and a distance between the bead base side portion of the bead core and the ply cord [minimum value of t is 0, f tphm] is set between the bead portion and the carcass ply cord.
or more, and the maximum value is below the groove line J, Om, preferably K, O
mm or less, and in this case, the flipper is designed to surround more than the circumference of the bead core, dispersing the force acting between the ply cord and the bead core, so that even if the load is over 6.0ψ-, the bead core This prevents layer separation between the ply cord and the ply cord, thereby increasing the durability of the bead portion. By doing so, the number of bead cores in the tire of the present invention can be reduced compared to conventional tires.

! When the low value of the amount is less than 00r-, the sudare-woven organic fiber layer (
・If the maximum value of l exceeds J,0-, cracks will occur at the end of the ply cord, which is undesirable. ・This will reduce the binding force of the bead core of the ply cord. ◎ Also, as the material for the organic fiber layer used in the flipper, 4 nylon, 6-4 nylon 1 polyester, and ray-eye are preferably used. ◎ The bead base side portion of the bead core in the present invention As shown in the 1st W3B, 弘＠Y indicates the tire bead base.
In the present invention, the rubber material on which the flipper is installed is a mixture of natural rubber too-so parts by weight and diene. system polymers, such as synthetic imprene rubber, styrene-butadiene copolymer rubber,
A vulcanizable rubber material consisting of at least 11 grams to 60 parts by weight selected from the group consisting of polybutadiene-ethylene-propylene terpolymer rubber and polyimbutylene, and 6. J' or more,
It is preferable that the amount of substances extracted by a mixed solvent of acetone and chloroform after vulcanization is 1 or less.

This is flipper-rubber hardening is 6! When it is above, the bead stiffness becomes high, and when the extracted amount of rubber is less than t weight, the crack growth property of the rubber is significantly improved, so that the growth of one bulge between the bead core and the carcass ply is mutually improved. The present invention will be described below with reference to the drawings.@Example 1 Figure 1 shows a cross section of the bead part TB8iooo-JQ
/4 CPIL tires and worked as a tire worker.

This tire has a bead core, and the load applied to the core is 0, and the Jψ value is 0.Next, tire B is a tire with two bead cores. In this case, the load on the core is r,
4 kg/ex 0The bead part of this tire B is the first
Shown in Figure B. Then, FIG. 2 is an enlarged view of a-b-c-dWI1 in FIG.

J is bead cover tape, 3 is bead core,! This is the Bakakacus ply code. In addition, l in Fig. 2 is the distance between the bead wire and the ply cord, a is the distance between the fibers of the flipper adjacent to the bead wire, b is the width of the fiber, /, +
, indicates coverage.

These tire engineers and B used a specially resilient rubber material for the tread rubber material to suppress failures in the tire crown portion. I for tire B
A friend made 20 types of tires by varying the values of O, J-2, 6ms, and □ from 0a+b to 4.

The tire and B have an internal pressure of 4.71 kg/m' and a load of 2.
．． Drum running at 700 hrs/h 〇kym/He After %/210 hours, cut the tire in the radial direction and check details 11
KI! As it turned out, the tire engineer only had cracks of less than O6λays between the bead core and carcass ply cord even at medium and high heights, whereas in Tire B, cracks of less than O6λays had occurred between the bead core and the carcass ply cord.
Depending on the value of (a + b), cracks of 0 to Jt1m are observed, and in tires with cracks of 0 to Jt1m or more, it is observed that part of the flipper thread is broken and the inside of the galley 1 cord is fibrillar. Ta.

Next, remove all running parts of Tire B in the tire radial direction.

After cutting out 0 pieces of the bead part at ridge intervals and finishing it with a puff, take a photo at io times magnification and observe the length and shape of the cracks around the core in the area below the top of the bead core.
The maximum crack length among the locations and the fritz percolation adjacent to the bead core at that location.

Determine the bead core coverage rate (-ya,) and the bead core/ply cord distance (1) e, (b, /a+,),
The relationship between (1) and cracks is shown in Figure 3, and from the results of more than 60 tests, the larger the distance (1) between the bead core and the ply cord, the more the stress between the ply cord and the bead core is relaxed. 1 from the fact that cracks are occurring from the threads of the cord! It can be seen that by decreasing /, +b, the number of defects decreases, and it is possible to prevent cracks from becoming larger due to continuation of defects at instants @ Example 2 In this example, TBS 1000-20 /≠PR dormitory carcass ply cord number Nylon / 190.46 pieces, tires with a small bead core were made with flipper rubber, flipper gauge, and flipper drive area as shown in Table 1, and 10 types of tires A to J were made into P11 tires. The fiber cords for flippers made in batches are all made of polyester.
≠0,4 was used. Among these, Tire J has a rubber layer instead of a flipper. For each tire, the bead part is cut in the tire radial direction, the surface is puffed and smoothed, and then microindentation soda is applied. tester (Wm-11ac, manufactured by Co., Ltd.)
The value of IO seconds after positive load measured in 1 was defined as rubber acid & (HD) and is shown in Table w11. For the extracted extraction valve, a part of the flipper including the rubber thread was carefully collected from the tire with a knife, the total weight was measured, and then extracted under reflux for 2 hours with a solution of acetone:chloroform (1:1), and then vacuum dried (R, T, for J hours), the weight was measured, and the fraction of the weight was used as the extraction valve, and the ratio to the initial weight was shown in Table 1.

Next, as in the case of Example 1, apply an internal pressure of 4.71 Tqlt, load, :Z, 700- to the other seven tires of various types, and set the speed to 1 at a speed of ≠0111F/Hr! The length of the crack that occurred after running the drum for 0 hours and the electrical equipment at the end of the ply cord were observed. Table 4I-1...Japan Synthetic Rubber Co., Ltd. jaw 8BR1500 umbrella 2.
...HAF sheet 5. Manufactured by Tokai Riki-Gen, product name *1...
・TSKURAK 81ONA, manufactured by Ouchi Shinko Kagaku Co., Ltd.

Product name Rice 4...Koramoretsufu 000 manufactured by Nippon Oil, product 1
Rice 5...N-oxydiethylene-2-benzothiazolylsulfenamide Tsukusela M8A-ν Manufactured by Ouchi Shinko Kagaku Co., Ltd., trade name.

From the results in table s1, the minimum distance between the bead base side portion of the bead core and the ply cord is 0. It can be seen that if the maximum core coverage ('L) of the inner 7 ripper is equal to or greater than Inm and is less than or equal to San〇hatake+b, it can be achieved at least the same level as that of the bead core counselor. It is also understood that bead durability is further improved if the hardness of the 7 ripper rubber is 61 or more and the extraction valve is 1 or less.

Example 5 1000-n20. / 2 from carcass ply with a tire with a third ply rating! Koo s14's PIilT
A radial tire with an actual ply number of J plies for code delivery was examined.

As in Example 1, the tread rubber had a high rebound elasticity, and the tires shown in Table 8 were made as trial tires. Used flipper
The rubber was 6 Nylon/T Hiro Od/2, and the rubber shown in Table 11!2 (A) was used as the 7 Ritzper coating rubber.

Table 8 shows 9T possible, / , ) (D), and the extracted weight ratio was measured from a tire manufactured at the same time and made in the same process.

In addition, since the tire is a radial tire, it
is the tire bead inner diameter W! The tires were cut in the radial direction at a deviation of 1O-J70 from the perpendicular line and measured from the cross section of the bead section.◇These tires were loaded with an internal pressure of t and z#/cm and a load of 3,000kg. My friend ran the drum at 41LOkm/Hr. The results are shown in Table 3 as an index when the running time until bead failure is set to 10Q for a human.

As is clear from the table, it is certain that B and C of the present invention improve the durability at the bead part. The stress applied between the carcass cord and the bead core is alleviated, and the stress acting between the carcass cord and the core causes cracks in the rubber between them, which can lead to the carcass cord breaking.It is possible to increase the fire resistance of the bead part. became. This means that even if the load applied to the seven bead cores in a large tire is increased, the product life remains the same as before, and the number of bead cores can be reduced. This can greatly contribute to productivity improvements in terms of manufacturing bead cores for large bias tires and reducing man-hours during tire molding.◎

[Brief explanation of the drawing]

Figures 1 and B are cross-sectional views of the bead portion of a tire as an example of the present invention, Figure 1 is a reed diagram of section 5-b-c-d in Figure 1B, and Figure 3 is a cross-sectional view of a tire according to the second embodiment. FIG. 2 is a diagram showing the length of cracks in the core circumferential dyeing below the upper end of the bead core of the test tire. /...Flipper adjacent to the bead core, CO...Flipper-1J...Bead cover tape, Hiroshi...Bead core,! ...Carcass ply cord. Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] 1. The carcass ply cord having one or more pairs of bead cores in the left and right bead portions and connecting the left and right bead cores forming an O-sealed tube is an organic Im! In a pneumatic low-traffic tire that is constructed in a horizontal manner and has a load per unit length applied to one bead core of 4,011/1 or more, a bead base side portion of the bead core is provided between the bead core and the ply cord in the bead portion. 1 or more sudare-woven organic fiber layers (flippers) are arranged around 3 or more times around the bead core so that the minimum value of the distance between the ply cord and ply cord is 0.1 wtm or more and the maximum value is 3.00 or less. A pneumatic tire characterized by the following: 2. In the organic fiber layer surrounding the bead core, the bead core placement ratio of the organic fibers in the organic fiber layer closest to the bead core is greatest around the bead core 41101
Claim # that is less than or equal to 1! @ Pneumatic tires described in item 1. S, the rubber material in which the organic fiber layer is embedded is natural rubber 100~
It is a vulcanizable rubber material consisting of 0 to 60 parts by weight of a diene polymer and a diene polymer, and has a hardness of 6 parts by weight after tire vulcanization.
! The pneumatic tire according to claim 1 or 2, wherein the amount of the substance extracted by the mixed solvent of acetone and Kurodaform after vulcanization is 1 weight or less.